Hyperoxia / High FiO₂ ExposureNCT07551869
Oxygen as a Metabolic Modulator: Divergent Physiological Adaptations to Hypoxic and Hyperoxic Tabata Training.
A study testing FIO2 modulation during HIIT protocol on assault bike in people with Hyperoxia / High FiO₂ Exposure and Interval Training, run by Haute Ecole Bruxelles-Brabant at 1 site in Belgium.
Trial summary
The purpose of this study is to examine how breathing air with different oxygen concentrations (higher or lower than normal) during high-intensity interval training affects: Aerobic capacity (VO₂max) Ventilatory thresholds Blood lactate levels Perceived exertion This research aims to better understand how oxygen… Read more about this study
- Who is it for?
- Ages 19 to 35 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Hyperoxia / High FiO₂ Exposure, Interval Training, HIIT
- What is being tested?
- FIO2 modulation during HIIT protocol on assault bike
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 23 participants
- Where
- 1 siteBelgium
- Study dates
- 10 Jan 2023to 15 Dec 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 19 to 35 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- recreationally active
- male
- 18-35 years old
Who cannot join
- engaged in professional or elite-level sports training
- cardiovascular, pulmonary, metabolic, or neurological disease
- taking medications known to influence cardiovascular or metabolic responses to exercise To minimize potential confounding factors, participants were instructed to refrain from strenuous physical activity, alcohol consumption, caffeine intake, and smoking for at least 24 hours before each testing session, in accordance with standard exercise testing procedures recommended in exercise physiology guidelines
Trial locations and contacts
1 site in 1 country.
Belgium1 site
Haute Ecole Bruxelles Brabant - HE2B
Brussels, Brussels Capital, 1040
About this study
The purpose of this study is to examine how breathing air with different oxygen concentrations (higher or lower than normal) during high-intensity interval training affects:
- Aerobic capacity (VO₂max)
- Ventilatory thresholds
- Blood lactate levels
- Perceived exertion This research aims to better understand how oxygen availability influences physiological adaptations to exercise.
Read more
If you agree to participate, you will undergo the following:
Baseline testing:
- Cardiopulmonary exercise test (cycling until exhaustion)
- Measurement of oxygen consumption, heart rate, and ventilatory thresholds
- Blood lactate measurement (finger prick)
Training intervention (3 weeks):
- 3 sessions per week (total of 9 sessions)
- High-intensity interval training (Tabata protocol: 8 × 20 seconds effort / 10 seconds rest)
- Exercise performed on an air-resistance cycle ergometer
During training, you will breathe either:
- Hyperoxic air (high oxygen concentration) or
- Hypoxic air (low oxygen concentration) You will be randomly assigned to one of these conditions.
Post-intervention testing:
- Same assessments as baseline
The risks associated with this study are similar to those encountered during high-intensity exercise:
- Fatigue
- Muscle soreness
- Shortness of breath
- Temporary discomfort from finger-prick blood sampling
Breathing altered oxygen concentrations (hypoxia or hyperoxia) may induce:
- Mild dizziness
- Increased breathing effort (hypoxia)
- Sensations of ease or altered effort perception (hyperoxia) All sessions are supervised by trained personnel, and safety monitoring is ensured throughout the study
You may benefit from:
- Improved physical fitness
- Detailed physiological assessment (VO₂max, thresholds) However, no direct health benefit is guaranteed. Your participation is entirely voluntary.
- You may withdraw at any time
- You do not need to provide a reason
- Withdrawal will not affect your academic or professional standing
All collected data will be:
- Anonymized
- Stored securely
- Used only for research purposes Your identity will not be disclosed in any publication. Data will be handled in accordance with applicable data protection regulations (GDPR).
You have the right to:
- Access your data
- Request correction or deletion where applicable
- Conditions
- Hyperoxia / High FiO₂ Exposure, Interval Training, HIIT, High Intensity Interval Training, VO2max, Hypoxia
- Being tested
- FIO2 modulation during HIIT protocol on assault bike
- Keywords
- Human, HIIT, High Intensity Interval Training, Assault-Bike, VO2max, Tabata training, Hypoxia, Hyperoxia
- Medical subject headings
- Hyperoxia, Hypoxia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
FIO2 modulation during HIIT protocol on assault bikeOther
Normobaric hyperoxic breathing during high-intensity interval training (FiO2 0.60) and hypoxic (FiO2 0.16)
| Study group | Role | What they receive |
|---|---|---|
| Hyperoxia group | Experimental | inspired oxygen fraction (FiO₂) = 0.60 during Tabatha protocol Receives: Other: FIO2 modulation during HIIT protocol on assault bike |
| Hypoxia group | Experimental | inspired oxygen fraction (FiO₂) = 0.16 during Tabatha protocol Receives: Other: FIO2 modulation during HIIT protocol on assault bike |
What is being measured
The primary outcome is the main question the study is designed to answer.
maximal oxygen uptake (VO₂max)
VO2max represents the maximal rate at which an individual can consume oxygen during incremental exercise. It is measured during a graded exercise test (e.g., treadmill or cycle ergometer) using indirect calorimetry. It reflects aerobic capacity and cardiovascular fitness. Higher values indicate better aerobic performance and endurance capacity.
Measured: From enrollment to the end of protocol at 3 weeks
Secondary outcomes (3)
the first and second ventilatory thresholds (VT1, VT2)
VT1 (first ventilatory threshold) corresponds to the exercise intensity at which ventilation begins to increase disproportionately relative to oxygen uptake, indicating the onset of lactate accumulation. VT2 (second ventilatory threshold) marks a further disproportionate increase in ventilation due to metabolic acidosis. These thresholds are determined from gas exchange analysis during exercise testing and reflect submaximal aerobic and anaerobic transition points.
Measured: from enrollment to the end of the protocol at 3 weeks
peak blood lactate
Peak blood lactate is the highest concentration of lactate measured in the blood during or immediately after maximal exercise. It is assessed via capillary or venous blood sampling. This measure reflects the degree of anaerobic metabolism and glycolytic contribution during high-intensity effort.
Measured: from enrollment to the end of protocol at 3 weeks
session rating of perceived exertion (RPE).
RPE is a subjective measure of exercise intensity based on an individual's perception of effort, typically assessed using standardized scales such as the Borg scale (6-20 or 0-10). It integrates physiological and psychological responses to exercise and is useful for monitoring training load and tolerance.
Measured: from enrollment to the end of the protocol at 3 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Apr 2026
- Study start10 Jan 2023
- Primary completion10 Jun 2023
- Study completion15 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for Hyperoxia / High FiO₂ ExposureStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- randomized, two-arm, parallel-group controlled trial
- Masking
- None (open label)
- Enrolment
- 23 participants (actual)
Sponsor and investigators
- Lead sponsor
- Haute Ecole Bruxelles-Brabant
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Costantino Balestra, Haute Ecole Bruxelles-Brabant
- Investigators
- Clément Levêque, PhD, Study director, HE2B
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07551869
- Sponsor's protocol ID
- B200-2020-088
- Status last verified
- Apr 2026
- First submitted
- 5 Apr 2026
- Last updated
- 30 Apr 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Data are collected for this study only. The experiments opens new questions and so new data collection
Publications
Balestra C, Lambrechts K, Mrakic-Sposta S, Vezzoli A, Levenez M, Germonpre P, Virgili F, Bosco G, Lafere P. Hypoxic and Hyperoxic Breathing as a Complement to Low-Intensity Physical Exercise Programs: A Proof-of-Principle Study. Int J Mol Sci. 2021 Sep 4;22(17):9600. doi: 10.3390/ijms22179600.
PubMed 34502508Balestra C, Mrakic-Sposta S, Virgili F. Oxygen Variations-Insights into Hypoxia, Hyperoxia and Hyperbaric Hyperoxia-Is the Dose the Clue? Int J Mol Sci. 2023 Aug 30;24(17):13472. doi: 10.3390/ijms241713472.
PubMed 37686277Balestra C, Kot J. Oxygen: A Stimulus, Not "Only" a Drug. Medicina (Kaunas). 2021 Oct 25;57(11):1161. doi: 10.3390/medicina57111161.
PubMed 34833379
Study at a glance
From the registry record, last updated by the sponsor on 30 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Oxygen as a Metabolic Modulator: Divergent Physiological Adaptations to Hypoxic and Hyperoxic Tabata Training.
- ClinicalTrials.gov ID
- NCT07551869
- Acronym / sponsor ID
- B200-2020-088
- Conditions
- Hyperoxia / High FiO₂ Exposure, Interval Training, HIIT, High Intensity Interval Training, VO2max, Hypoxia
- Keywords
- Human, HIIT, High Intensity Interval Training, Assault-Bike, VO2max, Tabata training, Hypoxia, Hyperoxia
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 23 participants (actual)
- Lead sponsor
- Haute Ecole Bruxelles-BrabantUniversity, hospital or other
- Study start
- 10 Jan 2023 (actual)
- Primary completion
- 10 Jun 2023 (actual)
- Study completion
- 15 Dec 2025 (actual)
- First posted
- 27 Apr 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to examine how breathing air with different oxygen concentrations (higher or lower than normal) during high-intensity interval training affects:
- Aerobic capacity (VO₂max)
- Ventilatory thresholds
- Blood lactate levels
- Perceived exertion This research aims to better understand how oxygen availability influences physiological adaptations to exercise.
If you agree to participate, you will undergo the following:
Baseline testing:
- Cardiopulmonary exercise test (cycling until exhaustion)
- Measurement of oxygen consumption, heart rate, and ventilatory thresholds
- Blood lactate measurement (finger prick)
Training intervention (3 weeks):
- 3 sessions per week (total of 9 sessions)
- High-intensity interval training (Tabata protocol: 8 × 20 seconds effort / 10 seconds rest)
- Exercise performed on an air-resistance cycle ergometer
During training, you will breathe either:
- Hyperoxic air (high oxygen concentration) or
- Hypoxic air (low oxygen concentration) You will be randomly assigned to one of these conditions.
Post-intervention testing:
- Same assessments as baseline
The risks associated with this study are similar to those encountered during high-intensity exercise:
- Fatigue
- Muscle soreness
- Shortness of breath
- Temporary discomfort from finger-prick blood sampling
Breathing altered oxygen concentrations (hypoxia or hyperoxia) may induce:
- Mild dizziness
- Increased breathing effort (hypoxia)
- Sensations of ease or altered effort perception (hyperoxia) All sessions are supervised by trained personnel, and safety monitoring is ensured throughout the study
You may benefit from:
- Improved physical fitness
- Detailed physiological assessment (VO₂max, thresholds) However, no direct health benefit is guaranteed. Your participation is entirely voluntary.
- You may withdraw at any time
- You do not need to provide a reason
- Withdrawal will not affect your academic or professional standing
All collected data will be:
- Anonymized
- Stored securely
- Used only for research purposes Your identity will not be disclosed in any publication. Data will be handled in accordance with applicable data protection regulations (GDPR).
You have the right to:
- Access your data
- Request correction or deletion where applicable
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- randomized, two-arm, parallel-group controlled trial
| Arm | Type | Receives |
|---|---|---|
| Hyperoxia group | Experimental | Other: FIO2 modulation during HIIT protocol on assault bikeinspired oxygen fraction (FiO₂) = 0.60 during Tabatha protocol |
| Hypoxia group | Experimental | Other: FIO2 modulation during HIIT protocol on assault bikeinspired oxygen fraction (FiO₂) = 0.16 during Tabatha protocol |
Who may qualify
- Ages
- 19 to 35 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- recreationally active
- male
- 18-35 years old
Key exclusion criteria (3 listed)
- engaged in professional or elite-level sports training
- cardiovascular, pulmonary, metabolic, or neurological disease
- taking medications known to influence cardiovascular or metabolic responses to exercise To minimize potential confounding factors, participants were instructed to refrain from strenuous physical activity, alcohol consumption, caffeine intake, and smoking for at least 24 hours before each testing session, in accordance with standard exercise testing procedures recommended in exercise physiology guidelines
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| FIO2 modulation during HIIT protocol on assault bikeNormobaric hyperoxic breathing during high-intensity interval training (FiO2 0.60) and hypoxic (FiO2 0.16) | Other | Hyperoxia group, Hypoxia group |
Primary outcome
maximal oxygen uptake (VO₂max)
Time frame: From enrollment to the end of protocol at 3 weeks
VO2max represents the maximal rate at which an individual can consume oxygen during incremental exercise. It is measured during a graded exercise test (e.g., treadmill or cycle ergometer) using indirect calorimetry. It reflects aerobic capacity and cardiovascular fitness. Higher values indicate better aerobic performance and endurance capacity.
3 secondary outcomes
the first and second ventilatory thresholds (VT1, VT2)
Time frame: from enrollment to the end of the protocol at 3 weeks
peak blood lactate
Time frame: from enrollment to the end of protocol at 3 weeks
session rating of perceived exertion (RPE).
Time frame: from enrollment to the end of the protocol at 3 weeks
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Apr 2026.
- Background: PubMed 34502508Balestra C, Lambrechts K, Mrakic-Sposta S, Vezzoli A, Levenez M, Germonpre P, Virgili F, Bosco G, Lafere P. Hypoxic and Hyperoxic Breathing as a Complement to Low-Intensity Physical Exercise Programs: A Proof-of-Principle Study. Int J Mol Sci. 2021 Sep 4;22(17):9600. doi: 10.3390/ijms22179600.
- Background: PubMed 37686277Balestra C, Mrakic-Sposta S, Virgili F. Oxygen Variations-Insights into Hypoxia, Hyperoxia and Hyperbaric Hyperoxia-Is the Dose the Clue? Int J Mol Sci. 2023 Aug 30;24(17):13472. doi: 10.3390/ijms241713472.
- Background: PubMed 34833379Balestra C, Kot J. Oxygen: A Stimulus, Not "Only" a Drug. Medicina (Kaunas). 2021 Oct 25;57(11):1161. doi: 10.3390/medicina57111161.
- Individual participant dataSharing planned: No. Data are collected for this study only. The experiments opens new questions and so new data collection
Related trials for Hyperoxia / High FiO₂ Exposure
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Hyperoxia / High FiO₂ Exposure, Uric Acid/Albumin Ratio (UAR)
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Clément Levêque, PhD study director
HE2B
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing FIO2 modulation during HIIT protocol on assault bike in people with Hyperoxia / High FiO₂ Exposure and Interval Training, run by Haute Ecole Bruxelles-Brabant at 1 site in Belgium.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 30 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Belgium. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
maximal oxygen uptake (VO₂max) (time frame: From enrollment to the end of protocol at 3 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07551869, which also lists 3 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 Apr 2026.